Targeted VEGFA therapy in regulating early acute kidney injury and late fibrosis

Elevated hydrostatic pressure disturbs expression of growth factors in human renal epithelial cells

Obstructive uropathy is a common kidney disease caused by elevated hydrostatic pressure (HP), but relevant molecular and cellular mechanisms have not yet been well understood. In this study, we ex vivo investigated the effects of elevated HP on human renal epithelial cells (HREpCs). Primary HREpCs were subjected to 100 cmH2O HP for 8 or 48 h. Then, the cells were cultured without HP stimulation for another 24 h or 72 h. Cell morphology showed almost no change after 8h HP treatment, but exhibited reversible elongation after 48h HP treatment. HP treatment for 8 h increased the expression of TGFB1 and VEGFA but decreased the expression of CSF2 and TGFB2. On the other hand, HP treatment for 48 h downregulated the expression of CSF2, TGFB2, PDGFB, VEGFA, and VEGFB, while upregulated the expression of TGFB3. Interestingly, all changes induced by 48 h HP treatment were detected more severe compared to 8 h HP treatment. In conclusion, elongated ex vivo HP loading to renal epithelial cells induces reversible changes on cell morphology and disturbs the expression of several growth factors, which provides novel mechanistic insight on elevated HP-caused kidney injury such as obstructive uropathy.

Modified Zhenwu Tang delays chronic renal failure progression by modulating oxidative stress and hypoxic responses in renal proximal tubular epithelial cells

Background

Tubulointerstitial fibrosis (TIF) is a critical pathological feature of chronic renal failure (CRF), with oxidative stress (OS) and hypoxic responses in renal proximal tubular epithelial cells playing pivotal roles in disease progression. This study explores the effects of Modified Zhenwu Tang (MZWT) on these processes, aiming to uncover its potential mechanisms in slowing CRF progression.

Methods

We used adenine (Ade) to induce CRF in rats, which were then treated with benazepril hydrochloride (Lotensin) and MZWT for 8 weeks. Assessments included liver and renal function, electrolytes, blood lipids, renal tissue pathology, OS levels, the hypoxia-inducible factor (HIF) pathway, inflammatory markers, and other relevant indicators. In vitro, human renal cortical proximal tubular epithelial cells were subjected to hypoxia and lipopolysaccharide for 72 h, with concurrent treatment using MZWT, FM19G11, and N-acetyl-l-cysteine. Measurements taken included reactive oxygen species (ROS), HIF pathway activity, inflammatory markers, and other relevant indicators.

Results

Ade treatment induced significant disruptions in renal function, blood lipids, electrolytes, and tubulointerstitial architecture, alongside heightened OS, HIF pathway activation, and inflammatory responses in rats. In vivo, MZWT effectively ameliorated proteinuria, renal dysfunction, lipid and electrolyte imbalances, and renal tissue damage; it also suppressed OS, HIF pathway activation, epithelial-mesenchymal transition (EMT) in proximal tubular epithelial cells, and reduced the production of inflammatory cytokines and collagen fibers. In vitro findings demonstrated that MZWT decreased apoptosis, reduced ROS production, curbed OS, HIF pathway activation, and EMT in proximal tubular epithelial cells, and diminished the output of inflammatory cytokines and collagen.

Conclusion

OS and hypoxic responses significantly contribute to TIF development. MZWT mitigates these responses in renal proximal tubular epithelial cells, thereby delaying the progression of CRF.

Luteolin blocks the ROS/PI3K/AKT pathway to inhibit mesothelial-mesenchymal transition and reduce abdominal adhesions

BACKGROUND

Postoperative abdominal adhesion (PAA) is a common postoperative complication. Clinically, various methods have been used to prevent the occurrence of PAA, such as drugs and physiotherapy; however, no satisfactory results have been obtained. Luteolin (LUT) is a natural flavonoid that reduces inflammation and acts as an antioxidant. This research aimed to examine the impact and mechanism of LUT in reducing PAA.

METHODS

C57/BL6 mice were used in vivo experiments. PAA model was established using a brush friction method. Visual scoring and hematoxylin and eosin staining were used to score the severity of adhesions. Network pharmacology was used to infer potential targets and core pathways of LUT. Hydrogen peroxide (H2O2) was used to induce oxidative stress in vitro, while the reactive oxygen species (ROS) assay kit was used to evaluate oxidative stress levels. Western blotting, cell immunofluorescence, and multiple immunofluorescence assays were used to detect α-SMA, vimentin, E-cadherin, collagen I, or AKT phosphorylation level. Scratch assay was used to detect cell migration.

RESULTS

LUT reduced the degree of PAA in mice. It attenuated H2O2-induced ROS production and reversed mesothelial-mesenchymal transition (MMT) in HMrSV5 cells. Network pharmacology analysis showed that LUT likely exerted anti-adhesion activity by regulating the PI3K-Akt signaling pathway. Phosphorylated Akt levels were significantly reduced in LUT-treated HMrSV5 cells. LUT also significantly reduced the expression of vimentin and collagen I in adherent tissues and upregulated E-cadherin expression.

CONCLUSION

LUT blocks the ROS/PI3K/AKT pathway, thereby inhibiting MMT and reducing PAA. To this end, LUT has potential in PAA therapy.

BREAKING NEW GROUND: STANDARDIZING RAT MODELS FOR CRUSH SYNDROME INVESTIGATIONS

ABSTRACT

Crush syndrome (CS), alternatively termed traumatic rhabdomyolysis, is a paramount posttraumatic complication. Given the infeasibility of conducting direct simulation research in humans, the role of animal models is pivotal. Regrettably, the dearth of standardized animal models persists. The objective of this study was to construct a repeatable standardized rat CS models and, based on this, simulate specific clinical scenarios. Methods: Using a self-developed multichannel intelligent small-animal crush injury platform, we applied a force of 5 kg to the hind limbs of 8-week-old rats (280-300 g), subjecting them to a continuous 12 h compression to establish the CS model. Continuous monitoring was conducted for both the lower limbs and the overall body status. After decompression, biochemical samples were collected at 3, 6, 12, and 24 h. In addition, we created a CS model after resection of the left kidney (UNx-CS), which was conceptualized to simulate a more challenging clinical scenario to investigate the physiological and pathological responses rats with renal insufficiency combined with crush injury. The results were compared with those of the normal CS model group. Results : Our experiments confirm the stability of the crush injury platform. We defined the standardized conditions for modeling and successfully established rats CS model in bulk. After 12 h of compression, only 40% of the rats in the CS group survived for 24 h. Systemically, there was clear evidence of insufficient perfusion, reflecting the progression of CS from localized to generalized. The injured limbs displayed swelling, localized perfusion deficits, and severe pathological alterations. Significant changes were observed in blood biochemical markers: aspartate transaminase, lactate dehydrogenase, K+, creatine kinase, creatinine, and blood urea nitrogen levels rose rapidly after decompression and were significantly higher than the sham group. The kidney demonstrated characteristic pathological changes consistent with established CS diagnostic criteria. Although the UNx-CS rat model did not exhibit significant biochemical differences and pathological scores when compared with the standard CS model, it did yield intriguing results with regard to kidney morphology. The UNx-CS group manifested a higher incidence of cortical and medullary protein casts compared with the NC-CS group. Conclusion: We developed and iteratively refined a novel digital platform, addressing the multiple uncontrollable variables that plagued prior models. This study validated the stability of the platform, defined the standardized conditions for modeling and successfully established the CS model with good repeatability in bulk. In addition, our innovative approach to model a clinically challenging scenario, the UNx-CS rat model. This offers an opportunity to delve deeper into understanding the combined effects of preexisting renal compromise and traumatic injury. In summary, the development of a standardized, reproducible CS model in rats represents a significant milestone in the study of Crush syndrome. This study is of paramount significance as it advances the standardization of the CS model, laying a solid foundation for subsequent studies in related domains, especially in CS-AKI.

Cucurbit[8]uril-Based Supramolecular Probe for the Detection of 3-Nitrotyrosine in Human Serum and Plasma

The biomarker 3-nitrotyrosine (3-NT) is widely recognized as an indicator of renal oxidative stress injury, making its detection crucial for the early identification of renal insufficiency. This study presents the design and synthesis of a tetraphenylstyrene imidazole derivative (TIPE-MI), which is utilized to create a supramolecular probe in conjunction with cucurbit[8]uril (Q[8]) through host-guest interactions. The resulting supramolecular self-assembly exhibits excellent optical properties and has been employed for the specific detection of 3-NT through fluorescence quenching. The introduction of 3-NT resulted in a decreased fluorescence intensity of the yellow fluorescent probe, which gradually transitioned from bright yellow to light yellow and then became colorless as the 3-NT concentration was increased. A portable detection platform was devised to augment the efficiency of detection. In order to facilitate biological applications, we have substantiated the probe's exceptional precision in detecting 3-NT in biological samples, encompassing human serum and plasma. The probe also exhibited negligible cytotoxicity. The accumulation of the probe in renal cells elicited a fluorescence signal, thereby indicating the prospective viability of this system for visual detection with renal cytocompatibility.

Obesity blunts amelioration of cardiac hypertrophy and fibrosis by human mesenchymal stem/stromal cell-derived extracellular vesicles

Renovascular hypertension (RVH) can induce cardiac damage that is reversible using adipose tissue-derived mesenchymal stromal/stem cells (A-MSCs). However, A-MSCs isolated from patients with obesity are less effective than lean-A-MSC in blunting hypertensive cardiomyopathy in mice with RVH. We tested the hypothesis that this impairment extends to their obese A-MSC-extracellular vesicles (EVs) progeny. MSCs were harvested from the subcutaneous fat of obese and lean human subjects, and their EVs were collected and injected into the aorta of mice 2 wk after renal artery stenosis or sham surgery. Cardiac left ventricular (LV) function was studied with MRI 2 wk later, and myocardial tissue ex vivo. Blood pressure, LV myocardial wall thickness, mass, and fibrosis that were elevated in RVH mice were suppressed only by lean EVs. Hence, human A-MSC-derived lean EVs are more effective than obese EVs in blunting hypertensive cardiac injury in RVH mice. These observations highlight impaired paracrine repair potency of endogenous MSCs in patients with obesity.NEW & NOTEWORTHY Injection of A-MSC-derived EVs harvested from patients who are lean can resolve myocardial injury in mice with experimental renovascular hypertension more effectively than A-MSC-derived EVs from patients with obesity. These observations underscore and might have important ramifications for the self-healing capacity of patients with obesity and for the use of autologous EVs as a regenerative tool.